Card Protector Crystal Clear Envelope - 5-7/8" x 4-1/2" - Side Opening - Set of 5
The adhesive strip on this envelope won't snag your card as you put it in, because the strip is on the envelope itself, not on the closing flap.
This version has its flap on the side (the wider edge).
Acid and lignin free, archival safe. USPS approved envelope.