Q.D. Barb, 3/16, Silicone HP Tubing, to fit A-dec 300 and A-dec 500 Control Block; Pkg of 5For A-dec 500 & 300 Series Package of 5 A-dec, A-dec 500 and A-dec 300 are a registered trademark of A-dec, Inc.DCI has no affiliation with A-dec and A-dec has not authorized DCI replacement parts to be used on or in connection with A-dec products.