Stackable riser block for rear-mounted cycling trainers Unique 3-level design lets you select ideal training height Stacks with 2nd block to simulate climbing workouts Supports up to 12 adjustment levels with 2nd block Virtually indestructible injection-molded construction The CycleOps Riser Block's unique three level design, let's you pick a height for your front tire that will make your trainer riding time more comfortable and productive. You'll train harder and longer, because you'll be riding a more natural position. Enjoy a stable, worry-free ride in any rear-mounted cycling trainer with the CycleOps climbing riser block. The block features a unique three-level design that lets you select the training height, ensuring that your ride is comfortable and productive. You'll train harder and longer because you'll be riding in a more natural position. The riser block is also stackable: add a second block to simulate climbing workouts, with as many as 12 different adjustment levels. And the block is designed to last for years thanks to its virtually indestructible injection-molded construction. About CycleOps CycleOps believes building energy for positive change starts in the bike world, but it doesn't stop there. The company is passionate about creating space for cyclists in their communities, a process that reduces congestion and pollution while encouraging healthier, more active lifestyles. In addition to in-house local and national efforts, CycleOps supports the work of such organizations as the Bicycle Federation of Wisconsin, Bikes Belong, People for Bikes, and other key advocacy groups.