Type: MonocularExtension ring lengths are 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mmOuter diameter: 60mmPitch: 0.75External thread length: 3mm4 mm - internal thread length is 3 mm5 mm - internal thread length is 4 mm6mm - Internal thread length is 4.5mm7mm - Internal thread length is 5.5mm8 mm - internal thread length is 6 mm9 mm - internal thread length is 7 mm10-20mm internal thread length is 8mm