Hi Warren,
get all types….
I assume you mean the removable bolt-plates for hex-head bolts rather than fixed-hangers?
The older bolts are usually 3/8″ while the newer ones are usually 10 mm. 12 mm bolts are usually only used for rap anchors or belays and similar and not that much for protection on the rock. But not always…
Most bolts plates then are either suited to the 3/8″ or 10 mm, although the 10 mm ones will fit onto a 3/8″ but not always the other way around, so I usually go for the 10 mm – but often you get what is in the shop and that’s it.
However you will find that some bolts are slightly over-sized – either as someone has used something strange – like a 7/16″ (10.7 mm) or, if it’s a carrot (bash-in) then it may have expanded and the bolt-plate won’t fit.
As for 30 or 45 or 90 degree – it depends on the rock, the bolt and the climb, so I have all types. Some bolts are easier to clip and to get the crab through with one type, other with another type.
I hope this helps…
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