The Prime 16-48X50mm spotting scope combines a light weight compact design with the superior optical quality and clarity that Bushnell is known for. Fully Multi Coated - Multiple layers of anti-reflective coating on all air-to-glass surfaces deliver bright high-contrast images. Argon Purged Fog-Proofing - Argon-filled optics remain stable regardless of ambient temperature for the ultimate fog-proof protection. IPX7 Waterproof construction - O-ring sealed optics stay dry inside when immersed in three feet of water for up to 30 minutes.