The Rohl C4912 is a 1 1/2-inch extension kit. It is made out of reliable and long-lasting materials. This extension kit is used for the volume control rough-in valve A4911BO. It is also used with the following trims: the A4912, the A4712, the A2912, the A4012, the A4212, and the A4812. The Rohl C4912 1 1/2-inch extension kit is a representation of Rohl's goal to making products that are easy for the customers to install and use. This is available at a very cheap price. The House of Rohl has been in the business since 1983. They have reached success by providing distinctively different faucets and fixtures that define real luxury. To create superior products that will enhance your way of living is Rohl's goal.