We apologize for the confusion regarding the ID. The Legend T/S-603 1-1/4 in. PVC FPT x FPT True Union Ball Valve meets all the requirements of a 1” valve by industry standards (MSS SP 110). Although, the internal diameter (ID) of the valve is smaller than the ID of the tubing, this is necessary and common by all manufacturers so that the valve body is thick and strong enough to handle the stresses inherent of threaded union connections. We will update the information on this product to show the ID of 0.91". Please also note that there is a tolerance within the port size of -0.06".