This Kuster K1 Highchair Cushion Pack is compatible with the Kuster K1 Highchair. This is a must have accessory for any Kuster highchair. By adding the cushions the child will be more supported and with a little added comfort. This is machine washable which is great and for small messes this can be wiped over. By using the insert and the booster this gives added comfort once the child grows remove the booster and just use the insert.