Terminals are brass No. 10-32, it is desirable to use a 1.5 amp fuse in the secondary to protect the transformer, Model PT150-3.17 is desined specifically for 50 Hz operation at 66% reduce load. All other ratios are designed for 60Hz operation, Transformers are ANSI C57.13 group 1. Those Transformers marked with an * are group 2, For one primary, and one secondary fuse add to end of p/n PSF1. Approximate weight 8.0 lb, fully encapsulated. Indoor/ outdoor applications ( outdoor with optional boot)