3/8" with black tip

Thanks for reaching out to us. Odds are you have a 9/16" diameter balance, not 3/8". They never made a 3/8" tilt spiral balance with a black tip before, only for the larger size. 

When measuring diameter, you have to make sure you're only measuring the outer tube. Yours appears to be missing, presumably deteriorated. If you have an undamaged version then it would be a good idea to measure that instead to be positive. Otherwise, my recommendation would be our Series 600.