Comments about TFP Health Insurance Claim Form Window Envelopes; Self-Seal, 9 1/2Wx4 1/2H, 500/Box:
The self-stick works well, difficult (though not impossible) to un-stick and re-stick without evidence. So a 7 on security.
Note that ANY self-seal envelope isn't going to work well with laser printers. But the layout of this envelope (soft-cornered back) made it difficult for even our ink-jet to handle well. About 1/10th of the envelopes either had the return address improperly placed or unprinted at all!
Bottom Line No, I would not recommend this to a friend