Ateco 3-Piece Medium Coupler Set
Ateco 3-piece medium plastic coupler set. Don't let that extra ring throw you off - you'll just be using one at a time! The rings have different sized openings to fit pastry tips that fall in between small (standard) couplers and large couplers. Using the smaller ring this coupler will work with medium Ateco tips - those in the #800 series ending in 0-6. If there's any doubt just measure the base of your tip and if it's 1" in diameter this coupler will fit, even if it's another brand.
Using the larger ring this coupler will also work with large Magic Line and some Wilton tips - they just need to be 1 3/16" at the base.