This is the medium diameter axle peg - measuring 6 x 35mm - and is suitable for the following wheels (as shown in the first image) -
TW-1000 25mm Standard Wheels
TW-1500 38mm Standard Wheels
TWR-150 38mm Recessed Wheels
TWR-200 51mm Recessed Wheels
The installed shaft length is approximately 30.0mm long so to calculate the remaining peg that can be used once passed through the wheels, reduce this length (30mm) by the thickness of the wheel.
The wheels are available individually and drop 20% (to 0.16c each) when 100 or more are purchased. Simply add the appropriate number to the cart and the price will automatically be calculated.