Quality Park #8-5/8 White Double-Window Security Envelopes with Self Seal Closure - 500 PackQuality Park #8 5 8 Double Window envelopes have layered privacy features to keep checks secure. Reveal N Seal envelope flaps are perforated to show evidence of tampering. Security tint with pattern makes our envelopes difficult to read through, even when held to light. Double windows fit QuickBooks or other payroll and accounts payable checks. Patented fold in place closure won't seal prematurely. Just raise the bottom flap and press to seal. 24 lb.