2.0" collars will only work with 2.5" ID springs. Known to fit Polaris Robby Gordon 800-4, RZR 800-4, RZR XP900 (2 seat), RZR 900, RZR 1000S, Honda Talon (2-seat X, front and rear) and (4-seat X, front), Can-Am Commander, Can-Am Maverick (with 2.0" shocks); other models.
2.5" collars will only work with 3.0" ID springs. Known to fit front 2.5" IBP shocks on XP1000 Turbo (2 and 4 seat) and Fox Edition 1000; Honda Talon (2-seat R, front and rear) (4-seat X, rear), Can-Am Maverick with 2.5" shocks, front 2.5" IBP shocks on Can-Am Maverick X-3; Yamaha YXZ; other models.
3.0" collars will only work with 3.75" ID springs. Known to fit rear 3.0" IBP shocks on XP1000 Turbo (2 and 4 seat); Fox Edition 1000; rear 3.0" IBP shocks on Can-Am Maverick X-3; other models.