The SoLID Heavy Gas Cherenkov detector requires a window for its vessel that is made of a material that can hold high pressures for long periods of time and can do so with minimal bulging. Windows made of aluminum and carbon fiber were tested to see which material performs better. Different inner liner materials to use with the carbon fiber window, such as Tedlar and Mylar, were tested as well. In the tests, the total deformation of each window, as well as the leak rates, were found. The aluminum window had a maximum deformation of 4.5 cm when inflated to 1340 Torr and a minimum leak rate of (5±3)×10-5 Torr·L/s. This leak rate is equal to (2±1)×10-7 gs of C4F8 gas. The carbon fiber window’s maximum deformation was 4.4 cm when inflated to 1340 Torr and its minimum leak rate was (6.2±0.2)×10-3 Torr·L/s which converts to (2.0±0.1)×10-5 gs of C4F8 gas. The carbon fiber window leaked when used with a Tedlar inner liner and the bolt holes ripped when used with a Mylar inner liner, causing sealing failure. The aluminum window performs better, more consistently, and is easier to construct then the carbon fiber window, and therefore is the recommended choice.