Finally, your medium format and other cameras with retaining lugs can benefit from OP/TECH USA's patented weight reduction system. SUPER PRO STRAP(TM)is available in a choice of two clip designs to better fit the different camera models on the market. Op Tech has developed a unique locking slide mechanism which adds extra protection for a secure connection. Once the metal clip is attached to the retaining lug, the plastic locking slide is secured in position behind the metal clip. This prevents the clip from inadvertently opening. The slide must be removed before the clip will open.