This product has three features: 1. A patented one way roller bearing which keeps the saddle centered and prevents all side play. 2. A floating piston design that eliminates cavitations, when the post is laid on its side to be transported or hung upside down for storage. 3. The post also has a feature that is unique to its design. This is the external reservoir which has a patent pending. This reservoir allows for extra oil and air volume, which allows the post to provide consistent performance in a smaller diameter. This has been a feature that has eluded the competition and prevented other air-oil seat post systems from being offered in the 27.2 mm diameter.