In reply to John Kelly:
Not sure anything is good for 7.5mm. Lots of stuff with teeth will do 8mm (Petzl Tibloc, Basic Ascender, Croll, etc)
I have a RescueCender and like it, does 9-13mm
The Duck does 10.5-11mm
The Camp Goblin 10-11mm
Microtraxion does 8-11mm, I have a few of these for hauling, wouldnt want to take a drop on them tho
SAR Rocker does 10.5 to 12.7mm, (have lots of these)
The New (and OLD) Shunt 10-11mm singles, 8-11mm doubles
Ceri