This is a hard to find circa 1920s A.g. Spalding "Golfex" swing trainer. Very good condition.
This club originates from the famed Jeff Ellis Collection, and was featured in his book The Clubmaker's Art (TCA 2, p. 685). This club has not reached the collector market since its sale at the 2007 Sotheby's auction of The Jeff Ellis Collection. Included with this club is Page 685 from The Clubmaker's Art (2nd Edition) that has been signed by Jeff Ellis.