DANCO 1.91 in Replacement Cartridge for Delta Monitor Faucet 10347 - The Home Depot
Delta Faucet Cassidy 17 Series Dual-Function Shower Handle Valve Trim Kit, Chrome T17097 (Valve Not Included) 3.50 x 7.00 x 3.50 inches - Tub And Shower Faucets - Amazon.com
circa 1987 Delta shower valve cartridge replacement - DoItYourself.com Community Forums
Replacement for Delta Faucet Classic 13 Series Single-Function Shower Valve Trim Kit, Shower Handle, Valve Trim Kit, Shower Trim Kit, Matte Black T13020-BL(Cartridge Included, Valve Not Include) - Walmart.com