mm x inch x mm 20 × 1/2″ × 20 25 × 3/4″ × 25 32 × 1″ × 32 40 × 1.1/4″ × 40 50 × 1.1/2″ × 50 63 × 2″ × 63 75 × 2.1/2″ × 75 90 × 3″ × 90 110 × 4″ × 110