$65 as of my purchase is a very cheap price given how expensive battery packs are nowadays and is an easy recommendation by me. Easy installation and works great, I bought a GBA IPS screen kit and purple laminated shell as well and with everything connected I feel the battery lasted all day. also doesn't take long to fully charge back up so you'll be gaming more.
Installation is pretty straightforward but I reckon it needs a little installation note like.
1) remove left side battery prongs from GBA shell.
2) install battery into GBA.
3) connect battery to USB-C module board.
4) remove cooling copper tape from bottom and install on USB-C module board.
5) put on back cover.