These are Rovner ligature spare parts. Type 1 screws have a rectangular end, type 2 are rounded and shorter.
Rovner Ligature & Plastic Cap for Bass Clarinet - Dark Ligature for Hard Rubber Mouthpiece (3RL)
Rovner Ligature & Plastic Cap for Baritone Saxophone - Platinum Gold Ligature...
Rovner Ligature & Plastic Cap for Soprano Saxophone - Platinum Gold Ligature ...
Rovner Ligature & Plastic Cap for Alto Standard Saxophone - Dark Ligature for Ha
Rovner ligature LEGACY rubber for Bb clarinet LG-1R
Rovner Ligature Dark - Alto / Tenor Slim