Barkay Products Slim Sew Sewing Kit
Very compact sewing kit in a hard case. There's probably no smaller sewing kit that you could put on a carabiner or keychain.
- Can hang on a keychain
- Plastic case will crack if crushed
You could find much larger kits in a dollar store for less money, and you could find those cheap kits that come in flexible plastic envelopes, but the closest you'll get to the Slim Sew would probably be if you made your own from a pill bottle on a key chain. Those pill bottles are thicker though. You could also make a small Altoids tin sewing kit if you don't need to attach it to a key chain or carabiner.
It comes with six colors of thread, one yard of each color—black, white, red, blue, yellow, and green. For emergency repair use, like when you're out hiking and tear your pants, it seems like enough. For a home sewing kit it's probably not ideal.
I like that I could keep it in my key case and not think about taking it every day. An Altoids tin would be an extra thing to throw in my pocket, and I'm not sure it's a good idea to try jamming one of those little sewing kits that come in a flexible envelope into my wallet.
The case is rigid plastic. It's not polycarbonate or something made to take major impacts. Still, it seems strong enough for most situations.
The vinyl cap is friction fit, not screw on. It's pretty tight though. It doesn't seem likely that the Slim Sew will catch on something and pull out of the cap.
I've never sewed anything with the Slim Sew, but I have tested the strength of the ball chain by using it to pull off the cap multiple times. I tested the fit of the cap in high humidity, heat, cold, and sunlight. I tested the strength and clarity of the tube in various prolonged outdoor conditions. The Slim Sew passed all my tests.
Source: tested or reviewed it for the manufacturer (I make them)