Remo banjo head, weather resistant Weatherking Frosted Top, coated white, 10 7/16" medium collar 1007M1.
Diametre, measure your rim across the part that the head is stretch over, outside to outside and to the verticles in at least three direction with the head removed , take the average, (Add up the measurement s and devide by the number of measurements included) that is the diametre you require.
Collar heights, low for most arch tops unless they have a very wide tension hoop 5/8"or more where the strings pass over.
For flat tops measure the tension hoop where the strings pass over 3/8" requires a low, 7/16" a medium, 1/2" a high.
On some british banjos the head sits down behind the tension hoop, take the amount of rebate usually 1/8" from the tension hoop width, the remainder gives you the head require as above.
