Here's a classic Mid-Century Modern Oscillation Lawn Sprinkler dating to the 1970's.  Called the TO & FRO and made by Hancock-Gross of Philadelphia and is their Model 1970.  Made of aluminum tubing with cast fittings.  Sprinkler is New Old Stock and still sealed in the original box.  I chose not to unseal the box for a picture but it's depicted on the label and is guaranteed to please the new owner or I'll buy it back.  Check my Feedback.