These are the lightest full-strength biner I could find. They are definitely a mini-biner, which is fine if you reserve them for situations where you have two hands free (e.g. glacier travel, low 5th alpine rock, etc.) I would not want want to have to clip or these one-handed though (or unclip for that matter, the hook-nose really wants to grab the gear loop,) so I wouldn't use them for leading trad above 5.8 or so. I bought the set for the Ptarmigan Traverse and it trimmed almost 2 ounces off my minimal glacier travel kit. If you're really trying to shave every gram and apply them correctly, they're perfect!
This review was written in the old system and had content requirements that are different than reviews written today.