After reading around a bit there seems to be some varying opinions. See the quote: *These are the ones I've been looking for 
So far I've bought four boxes of these from ***, 2 boxes per order on two different orders. These are the ones to get. Don't get the SLBs from other suppliers. They don't work as good as these do. These have the wire that runs the length of the carto. The SLBs only heat at the tip of the wire. When that area drys out - and it dries out quickly - they start to burn. It's a really poor design.*
I have yet to see a burn and believe me we check em. I have the exact opposite experience, go figure huh.
So far I've bought four boxes of these from ***, 2 boxes per order on two different orders. These are the ones to get. Don't get the SLBs from other suppliers. They don't work as good as these do. These have the wire that runs the length of the carto. The SLBs only heat at the tip of the wire. When that area drys out - and it dries out quickly - they start to burn. It's a really poor design.*
I have yet to see a burn and believe me we check em. I have the exact opposite experience, go figure huh.