The SLB-25.4B-60NM from Laser 2000 (UK) Ltd. is a Optical Lens with Wavelength Range 400 to 700 nm, Focal Length -5.97 cm(-59.7 mm), Center Thickness 2 mm, Diameter 25.4 mm, Radius 6.228 cm(62.28 mm). More details for SLB-25.4B-60NM can be seen below.