However, the 8x 40mm Birders lack the 7x 36mm Birders' BaK-4 prisms, featuring instead lower grade BaK-7 glass and sport a porro prism system as opposed to the 7x 36s' phase coated roof prism system. The 8x 40mm Birders' also sport multi-coated optics and a non-slip rubber armor.
The 8x 40mm Birders' porro prism system is bulkier and more fragile than roof prism binoculars but also provides greater depth perception while their 40mm objective lens diameter provides enhanced brightness over smaller objective lenses as they let in more light. Their multi-coated optics provide the 8x 40mm Birders with higher-contrast viewing while also reducing eyestrain. Additionally, the 8x 40mm Birders are covered in a non-slip rubber armor that absorbs shock from light bumps as well as increasing grip.
