I know you get what you pay for, but this item is absolute rubbish! I got to use mine twice before it broke - the first time it was out by 4 kilos (reading 18 kilos whereas actual weight at airport was 22 kilos); the second time it broke in spectacular fashion - the needle fell out of the dial and the plastic face fell off a la Harold Lloyd style (it was actually quite funny). No surprise really as the whole thing is made of cheap plastic except for the metal hook by which you hold it. I reckon the packaging is worth more - it's certainly tougher as is quite difficult to get into.
A final point: it's very tricky to use and bounces around on the hook when you weigh a case - so the needle isn't steady and is hard to read (plus you have to bend down to read it, unless you're strong enough to raise the face up to eye level with a suitcase on the end).
So in summary: absolute rubbish. You'd be better off guessing the weight of your bag, or fashioning a rudimentary scale from bits of string, wood and stone.