While camping on the West Coast we bought a manual tin opener as we left our electric opener at home. What a disappointment firstly I had to use a stone to push the point through the tin, secondly the point was painted black and it all came of in the tinned food, thirdly it was blunt and could not cut the tin. At last I used a stake knife to complete te task sucsesfully. Now I was wondering do you ever test these things to see if it can do what it is supposed to do?