Ultracolor expandable poly string tie envelopes, top load, blue, 5/pack ultracolor expandable top load poly string tie envelopes tough, bright and big. Heavy-duty translucent polypropylene resists tears and repels moisture. Acid-free. 1-1/4″ expansion gusset. Letter size. Five envelopes per pack. [24 packs per carton.] blue larger quantity quotes available. Please call 1-888-978-7759. this product arrives to most customers in 2-3 business days.