The Peregrine is a dive computer focused on single gas air and nitrox diving, and light 3-gas nitrox technical diving. The Peregrine TX contains all the features of the original Peregrine but also includes more advanced features, such as air integration capability and a tilt compensated digital compass. A full comparison can be found here: Product Comparison Chart to learn more about the difference between the Peregrine and Peregrine TX.