An unlikely instrument for a band that never played one on record — until you trace the connection to John Lennon’s mother, Julia, who taught him “That’ll Be the Day” on her own banjo. That thread of authenticity is likely what pushed manufacturers to add a Beatles banjo to the wave of mid-’60s musical-instrument tie-ins.

This 11” cardboard tube let fans “hum along” to their favorite tunes through a colored flared mouthpiece (red, the rarest of four colors). Manufactured by Louis F. Dow under an NEMS license, the idea actually came from Merrimaker Corp., which traded away broad U.S. rights in exchange for exclusive resale privileges — a deal that later spun off a “Beatles Paper Hat” promo for a Chicago soft-drink bottler.