SMR - With Sliding Rail. This Gatemaster gate closer is suitable for gates up to 50kg in weight with a maximum width of 1000mm. The gate can be held open at 90° and it has two variable closing speeds for closing and latching. In situations where the pivot point on the gate does not line up with the pivot point on the closer then choose the SMR which includes a slide rail.. To suit gates up to 50kg. Two variable closing speeds for closing and latching. Can be used to hold gate at 90° angle.