"Material: Optical glass, class 1 grade B, per MIL-G-174A; Finish: Surfaces marked 'P' are polished, all others are ground; Anti-reflection coating: Multi-layer to MIL-C-675 PPE spec CS8; Paint: All ground surfaces painted according to PPE SS2; Dimensions: Inside diameter minimum 141.0 metric, maximum 141.5 metric; Outside diameter minimum 144.5 metric, maximum 145.0 metric"