OptiFlow Roller and Tray Kit gives you everything you need to roll on OptiFlow Epoxy Primer and OptiFlow Urethane Primer - trays, liners, two sizes of roller frames and rollers - everything to do the job right. Please remember, you will not get the same great results from standard hardware store rollers or regular primers that are designed to be used with a paint gun. The OptiFlow Roll-On Primer System includes specially formulated primers to be used with these specific rollers. Don\'t forget the OptiFlow Epoxy Primer (23130ZP)  which is perfect over bare metal, primers, bodyfillers and existing finishes. Plus it\'s designed to work with the OptiFlow Roller Kit. To get the body perfectly straight, you will want to apply the OptiFlow Urethane Primer (23132ZP)  which is perfect over OptiFlow Epoxy Primer and bodyfiller to sand and get your project laser straight. This primer is also Made in the USA and designed to work with the OptiFlow Roller Kit Contents: (1) Large, 7” Roller Frame (1) Small, 4” Roller Frame (4) 2-Packs, Large 7” Foam Roller Covers (total 8 pcs) (2) 2-Packs, Small 6” Foam Roller Covers (total 4 pcs) that fit the 4\" Roller Frames (1) Plastic Paint Rolling Tray (1) 12-Pack Paint Roller Tray Liners