Edstrom Automatic Water System Add On (single cage) The Edstrom Add-On kit consists of one standard valve & clip, one tee, two tubing standoffs and 4 feet of flex tubing. This is to add onto the Edstrom Automatic Water System Kit comes with everything you need to put your pet on an automatic water system which can be purchased separately. The Add-On works with the Edstrom Automatic Water System Kit which is Easy to Use, Easy to Install & fits most cages. Complete Starter Kit can be purchased separately.