Nimbus Double Quick Release Bolt Clamp.
Finally, a double quick-release seat post clamp!
No need to take tools to change your seat height on the trail or ride!
Aluminum body clamps with two steel bolts for extra clamping power! power! power!
A 22.2mm seat post uses a 25.4mm clamp.
A 25.4mm seat post uses a 28.6mm clamp.
A 27.2mm seat post uses a 31.8mm clamp.
Some Eclipse and Equinox frames need a 34.9mm clamp
These are a rule of thumb. Yet, variety exists.