> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt # Stackable 0.100″ Female Header with Extra 0.3″ Spacer: 2x20-pin, Straight **Type:** Product page · **SKU:** POLOLU-2749 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia) **Page:** https://core-electronics.com.au/stackable-0-100-female-header-with-extra-0-3-spacer-2x20-pin-straight.html ([markdown](https://core-electronics.com.au/stackable-0-100-female-header-with-extra-0-3-spacer-2x20-pin-straight.html.md)) This extra-tall stackable 40-pin female header features two rows of 20 pins spaced with a 0.1″ (2.54 mm) pitch. It includes three 0.1″-thick spacers for additional clearance, and the extended pins allow multiple units to be stacked as popularized on Arduino shields. The 2×20 size is notably used on the Raspberry Pi Models A+ and B+, and the extra 0.3″ of height allows for stacked boards to clear all of the components on the Raspberry Pi B+. ## Pricing - **Price:** $11.10 (inc GST) — $10.09 AUD, exc GST - **Quantity discounts:** 10+ $9.69 (exc GST) · 25+ $9.38 (exc GST) ## Availability & dispatch - In stock, ships same business day if ordered before 2PM (Australia/Sydney). - We can dispatch 2 today, and up to 200 more in 4–7 days. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=POLOLU-2749:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/POLOLU-2749:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description This stackable 40-pin female header features two rows of 20 pins spaced with a standard 0.1" (2.54 mm) pitch; this spacing is the same as on most [solderless breadboards](https://core-electronics.com.au/prototyping/breadboards.html) and matches [0.1" male header strips](https://core-electronics.com.au/0-100-2-54-mm-breakaway-male-header-2x40-pin-straight.html). The extended pins allow multiple units to be stacked as popularized on Arduino shields, enabling removable daughter boards that can access pins without blocking them. The 2×20 size is notably used on the [Raspberry Pi Model A+](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-2760) and Model B+ as well as the Raspberry Pi 2 Model B, Raspberry Pi 3 Model B, and [Raspberry Pi 3 Model B+](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-2797), and its height matches Pololu's [18.6 mm M2.5 standoffs for Raspberry Pi](https://core-electronics.com.au/aluminum-standoff-for-raspberry-pi-18-6mm-length-6mm-m2-5-thread-m-f-4-pack.html). | \| [![](https://core-electronics.com.au/attachments/localcontent/0J5967_17523805e48.jpg)](https://core-electronics.com.au/attachments/localcontent/0J5967_2052433a9c5.jpg) \| \|---\| | \| [![](https://core-electronics.com.au/attachments/localcontent/0J5968_13966034f91.jpg)](https://core-electronics.com.au/attachments/localcontent/0J5968_142456bfcdc.jpg) \| \|---\|---\| | |---| This header includes three 0.1"-thick spacers, which gives it the necessary height to clear everything all the components on the Raspberry Pi Model B+ or the Raspberry Pi 2 Model B. The locations of these spacers can be adjusted if so desired to provide more clearance, or they can be removed to provide less clearance: | [![](https://core-electronics.com.au/attachments/localcontent/0J5969_226560836d3.jpg)](https://core-electronics.com.au/attachments/localcontent/0J5969_1434402eade.jpg) | |---| | The spacers can be adjusted on the Stackable 0.100" Female Header with Extra 0.3" Spacer: 2×20-pin, Straight. | Pololu also carry a [shorter 2×20 stackable female header](https://core-electronics.com.au/stackable-0-100-female-header-2x20-pin-straight.html) (with no spacers) and a standard (non-stackable) [2×20 female header](https://core-electronics.com.au/0-100-2-54-mm-female-header-2x20-pin-straight.html). **Dimensions** | ![](https://core-electronics.com.au/attachments/localcontent/0J5971_57635ad98ed.jpg) | |---| | Dimensions (in mm) of straight stackable 0.100" female headers with extra spacers. | The dimensions in the above diagram are: **A = 48.3 mm**, **B = 51.3 mm**, **H = 16.1 mm**, and **P = 7.1 mm**. **People often buy this product together with:** | [![0.100" (2.54 mm) Female Header: 2x20-Pin, Straight](https://core-electronics.com.au/attachments/localcontent/0J5996_2940251c81.jpg)](https://core-electronics.com.au/0-100-2-54-mm-female-header-2x20-pin-straight.html) | [0.100" (2.54 mm) Female Header: 2x20-Pin, Straight](https://core-electronics.com.au/0-100-2-54-mm-female-header-2x20-pin-straight.html) | |---|---| | [![Aluminum Standoff for Raspberry Pi: 11mm Length, 6mm M2.5 Thread, M-F (4-Pack)](https://core-electronics.com.au/attachments/localcontent/0J7093_3353f85492.jpg)](https://core-electronics.com.au/aluminum-standoff-for-raspberry-pi-11mm-length-6mm-m2-5-thread-m-f-4-pack.html) | [Aluminum Standoff for Raspberry Pi: 11mm Length, 6mm M2.5 Thread, M-F (4-Pack)](https://core-electronics.com.au/aluminum-standoff-for-raspberry-pi-11mm-length-6mm-m2-5-thread-m-f-4-pack.html) | |---|---| | [![Aluminum Standoff for Raspberry Pi: 18.6mm Length, 6mm M2.5 Thread, M-F (4-Pack)](https://core-electronics.com.au/attachments/localcontent/0J7096_2719ffb75b.jpg)](https://core-electronics.com.au/aluminum-standoff-for-raspberry-pi-18-6mm-length-6mm-m2-5-thread-m-f-4-pack.html) | [Aluminum Standoff for Raspberry Pi: 18.6mm Length, 6mm M2.5 Thread, M-F (4-Pack)](https://core-electronics.com.au/aluminum-standoff-for-raspberry-pi-18-6mm-length-6mm-m2-5-thread-m-f-4-pack.html) | |---|---| **Dimensions** | Pins: | 2 x 20 | |---|---| | Spacing: | 0.100 in | | Weight: | 7.0 g | **General specifications** | Gender: | male-female | |---|---| | Pin type: | straight, stackable | | Current rating: | 3 A | ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/s/t/stackable_0.100_female_header_with_extra_0.3_spacer_2x20_pin_straight__pololu_2749__00.jpg)