The Vanguard QS-61 is a quick-Release Plate with 1/4" camera shoe in a removable slot. It works well with Vanguard ball head and pan heads.
Reviewed by 2 customers
I use this plate for astrophotography, generally with a Canon 60Da and lenses as heavy as the EF 70-200mm f/2.8L II, employing a Markins lens support, all on an Acratech ball head mount. It holds solidly.
This is one of the largest Arca-compatible plates made. It is very supportive and locks in solidly. Its length gives extra room for balancing what's on top. My only complaint is that it does not have capability for using a 3/8X16 screw. However, in the Arca-compatible line of kit, this is a big value. I have three of them, each used solely in different setups for doing astrophotography. Not having to change plates between the use of these setups is well worth the cost of these relatively inexpensive, but excellent quality, plates. I used one last evening to support a Borg 100ED, using its clamshell, with a Canon 60Da on an Acratech ball head. No problems at all. This is an excellent value piece of equipment. If it weren't, would I have bought the other two???!!!