Kajak Sport produce a range of hatch covers from very small round glovebox sized 10cm covers, through to some large ovals.
Many modern kayaks use the KS 20 (8" hatch), KS 24 (10" hatch) and oval hatch covers.
There are various compounds"
We also stock a range of rims to match if you are building or renovating your kayak.
Note that the VCP Replacement series are a different size / proportion from the other round and oval covers.