That will be a Holmes model 460 Speed King. The Early model 515 Road Kings, & the model 460 Speed Kings used the Identifier letter designation "R". The last Road King 515 was built in Jan. of 1940, & was serial no. RAO-318. The first model 460 was built in Jul. 1948, & was serial no. RG8-500, & the last built in Apr., 1958 ser. no. RD8-3680. Your ser. no. RH1-1281, decifers to, "R" = 460 Speed King, "H" = August, "1" = 1951, "1281" = unit built. Nice unit. Can't wait to see it installed.
