The KT-603 relays are from Kushiro/Kyota a supplier we currently don’t carry. A possible alternative option is the Omron series G5LE. Please click on this link https://www.digikey.com/short/q8df9q2p and choose the coil voltage and contact form to see the options available. Please make sure to review the datasheet G5LE (omron.com) before ordering.
The TechForum Cross Reference category is for parts that Digi-Key does not sell or parts that have gone obsolete. Our Engineers and Techs have reviewed the specifications for these parts and made a recommendation for a replacement. Please review the suggested part to ensure it will work for your application.