Not the glass described. - Redfield Revolt 10x42mm Binocular

Bought these for birding only to be greatly disappointed that the marketing was misleading. These have BK7 prisms not BAK-4. I specifically purchases these because of the BAK-4 prisms because they are much less grainy when viewing birds. It's a substantially difference for my purpose of use. Spend a little more and get some good binoculars that are as advertised.