Cannon Uni Stacker Releases

[laker1]

Discovered I have 2. Unfortunately I can not open them or understand how the tension is set?  Could someone advise me with a video or diagram on how these blessed things work?  Don’t want to break them. Have always used spring powered releases. 
thanks

jim

 

[laker1]

My apologies, but I figured it out. Going thru old stuff, sorting, throwing some of it out.