These are different crypto keychains.
Currently following coins are uploaded
ETC - Ethereum Classic
ETH - Ethereum
XRP - Ripple
ZEC - Zcash
XMR - Monero
Other will be uploaded in future.
Print in WHITE PLA or ABS, and than use permanent marker to color them.
Standard diameter is 30 mm and thickness is 2 mm to 2.5 mm.
If you want both side same then print two of them and join them using some quick glue.
You can suggest me via comment if any other coin you want to see in keychain.
use cura adaptive layers to reduce print time and improve accuracy, specially in ethereum and ethereum classic keychain