Here is a good working pneumatic control valve that was used to control an air over hydraulic spool valve on a recycling truck. These can be used on any manually controlled air over hydraulic spool valve system. I have 2 of these, 1 still has the aluminum mounting bracket attached to it. These have the ability to be stacked or mounted to each other off of 1 mounting point. They both worked with-out issue when removed. If you have any questions feel free to ask. The auction is for 1 valve with the option to buy both.