diff --git a/README.md b/README.md
index 2e28746e..2e8a22c6 100644
--- a/README.md
+++ b/README.md
@@ -224,12 +224,17 @@ when macos asks for the pin, touch the sensor.
 
 | part | used here | notes |
 | -- | -- | -- |
-| microcontroller | seeed studio esp32-s3 | needs native usb and hardware uart. secure boot + flash encryption strongly recommended |
-| fingerprint sensor | zw101-style uart sensor | uses the common `0xef01` packet protocol |
+| microcontroller | seeed studio esp32-s3 | needs native usb and hardware uart. secure boot + flash encryption strongly recommended. search: [xiao esp32s3](https://www.amazon.com/s?k=seeed+studio+xiao+esp32s3) / [esp32-s3 supermini](https://www.amazon.com/s?k=esp32+s3+supermini) |
+| fingerprint sensor | zw101-style uart sensor | uses the common `0xef01` packet protocol. search: [zw101 sensor](https://www.amazon.com/s?k=zw101+fingerprint+sensor) |
 | computer | macos | hid mode needs the helper. piv/pam mode needs macos smart card support |
 | case | printed top/bottom stl | `hardware/case/case_top.stl` and `hardware/case/case_bottom.stl` |
 | wiring/solder/etc | misc | whatever your build needs |
 
+these are amazon search links rather than links to individual listings, because
+sellers and listings for these parts come and go. check the specs on whatever you
+buy: the board needs native usb and a hardware uart, and the sensor needs to speak
+the `0xef01` uart protocol.
+
 other esp32-s3 boards should work if the usb and uart pins are available. other
 fingerprint sensors may work if they speak the same uart protocol. other
 microcontroller families can work, but are not currently supported.