These foams are designed to fit the Preonic - the number row expanded ortholinear keyboard by Jack Humbert of OLKB.com
** Important Information Regarding Foam **
If you select Black 4mm foam, you will be sent BLUE 4mm foam. Black 4mm is currently unavailable and no estimate on when it will be restocked. The blue foam is the correct thickness and even more dense so should be considered an upgrade.