This is a rather unusual tremolo bridge. As you can see in the second image, the strings are passed through each string lock screw and locked with the ball end of the string. I purchased it in this condition several years ago and have kept it in storage without using it. The tuning screw on the 6th string side is missing and replaced with a different screw, but you should be able to purchase a replacement, even if it's not the original. The arm is also missing, but a commercially available one should be a suitable substitute. Everything in the images is included.