I know what they're for. The choices for a 1/2A model battery pack are not so plentiful. I've used 220 and 300 mAh (32g) NiMH packs in the past, but I won't any longer, just had too much trouble with them. I can get 14g 200mAh 2s, 18g 250 mAh 2S, or 30g 430mAh 2s LiPo packs off the shelf at the LHS. These can be safely and repeatedly charged at 1C on my field charger which I always have available, and at this point I trust them. From a reliability standpoint regulators don't worry me. So this is the way I am going for 1/8A - A stuff. These are smaller then the 3A regulators I got earlier this year and I like the short leads and compact size. Haven't yet ordered anything from HK, not sure I plan to.