Manufacturer's part #06 LAI 001. Their price: $122.00. Made of SK 11 and SF 5 glasses. Cemented doublet with a wavefront distortion of 1/5th wave at 830nm, design wavelength is 830nm, center thickness is 3.5mm. edge thickness is 2.8mm. Surface quality is 60-40 scratch and dig. Cement is an Ultraviolet-cured polyester, coating is a Broadband Anti-reflective. Unused.