The picture clearly shows strap at the corner.  I expected 4 straps.  What I got were two straps, each about 1/3 the way from the end.  Very hard to put on the mattress.  I have two single XL mattresses.  The tension on the last strap to install is so much that one of them broke.  I haven't had then long enough to know how they wear nor how fade resistant they are.  Fabric is nice.  I have 14-inch mattresses.  The pockets are not too deep.