I'm using these on a VXII I bought some time back and I must say, I think they're an excellent product.  They have nice tight O-ring seals and magnets to help keep things closed.  They pop open easily with a lever on the eyepiece side and a tab on the objective.  They thread into the scope so there's no way they're going anywhere if you don't want them to.  I like them better than "comparable" products.  Just thought I'd let you know about my experiences in case anybody is interested.  MJD