Rocky's Eazy Roller® 321 Commercial Senior End Set with 4" Tubing. The Senior is the most popular of Rocky’s Eazy Rollers® Commercial Systems, it is designed to handle large covers (up to 100′ long, width dependent). It still comes with Rocky’s high quality 4″ locking castors, so it can be easily moved out of the way while you’re enjoying your pool. The extra strong base gives additional clearance and mass to the unit so it can handle the additional load. Just reel in the cover with the longer handle, release the anchor bolts and wheel it out of the way. It’s as simple as that. The Senior uses Rocky’s 12-sided, 4" anodized Commercial Tubing. This adds to the strength and capabilities of this commercial reel system.