The aluminum sliding pieces of the Tange/IRD Sliding Dropout. Also fits IRD Broski Dropouts
Left side has an IS disc tab. Right side has a derailleur hanger.
For QR hubs.
Your best option if you bent or cracked your derailleur hanger on a Soma Juice, Riff, Wolverine, Ritchey P-29 or Citizen.
Bolts not included.