PHAREGE 9x6x4 Shipping Boxes 18Pack, 6 Colors Gift Boxes Set

Would love to buy these in larger quantities. Is there any way to do so?

Are these durable enough to be sent in the mail without putting in another box?

Can you just order yellow boxes only?

Hi! do you offer these 12 x 9 x 4 inch boxes as a pack of 18 all in yellow? if so, i'd love to purchase around 20 packs of 18. thank you!