This inline thermostat housing allows you to remotely mount your thermostat in the top radiator hose line away from the engine. This is especially helpful when there is no longer any room on the block or in some LS engine applications when using an eletric water pump which eliminates the thermostat housing completely. It has 1-1/2'' (38mm) outlets and also has internal AN16 ORB ports so you can also run custom AN braided lines if you wish.