Tube diameter: 19mm 25.4mm"R": rubber covered"WA": wide angleGR29 4X15 $2.00GR30 4X20S $3.2GR31 4X20WA $3.0GR32 3-7X20 $5.2GR33 1.5-4.5X20 $12.65GR34 4X32 $8.8GR35 4X40 $10.0GR36 6X40 $10.2GR37 2-7X32 $13.4GR38 3-9X32 $12.7GR39 3-9X40 $14.0GR40 3-9X50 $16.3GR41 2.5-10X56 $30.0GR42 8X56 $27.8GR43 3-9X56 $30.0GR44 3-9X40R $16.0