Feed two straps through, one on each side of the center divider. When the straps are pulled from the direction of the small end they lock and can't travel. When straps are pulled from the wide end they travel freely. Pull center divider towards the wide end to free straps to travel in the other direction.

Scaled for straps up to 15mm wide.

Monoprice Select Mini

No

No

0.131

20%

Prints fine at 0.2, better details at 0.08.

To assemble: lay one of the spindle caps down on your work surface and place the main body on top sliding the peg up through the center spindle guide. Push the main spindle body down onto the cap peg until it's firmly in place. If necessary clean the holes in the top plate to make sure they are free from printer debris. Then push the top plate down onto the main body, I used some hobby clamps to push the top onto the main body pegs. Push the last spindle caps down onto the main spindle body through the top spindle guide.