Quoted from mskoenen:This is the locking one (red):
https://www.digikey.com/products/en?keywords=CKN10023-ND
This is the momentary one (black):
https://www.digikey.com/product-detail/en/c-k/F2UOA/401-1225-ND/417519
If you need new red or black button caps, they're near the bottom under "Associated Product".
Thanks for this - old thread, but just saved me hours of searching and frustration as Marco, PBL, etc. are all out of stock!