Niigata Engineering
Niigata Engineering S55013-0670-46K-386 (Pack of 2)
You will find that The epoxy resin store tests every batch for quality before shipping.
Niigata Engineering S55015-0355-46K-128 Feed Cylinder Seal Kit (Pack of 2)
A nice touch: the 6 inch size allows this to be used as a spacer or gauge in setups.