Johnson's Calibrated Stay Adjusters come in different configurations. This one is a stainless steel Jaw and Eye construction and can not come apart by an inexperienced crew or during the vibration of trailering on the road. Its terminal rod is made captive, therefore it can not turn and can not come apart when fully extended.
Adjustments are made by turning its knurled knob. It is designed for up to 5/32 in. (4mm) wire. It adjusts 2 in. (51mm).