10-Scale All-Plastic Beginner's Slide Rule
Teledyne-Post model 44BB-100 [1972+]  (Some [1972] marked model 1410)
Hemmi model P281

This appears to be another example of changing the model number after the slide rule had been manufactured.  Specimens with both model numbers exist but I'm sure Teledyne-Post never sold this rule under any model number other than 44BB-100.
1972 Teledyne-Post Slide Rule Catalog 

Top:  Teledyne-Post 1410.   Date code "^UI" (September 1970)
Bottom: Teledyne-Post 44BB-100.   Date code "^XE"  (May 1973)