Hi email@example.com, It's not on the TG website... However, you can contact TG Customer Support and order the hose from them. You can also get the exact replacement hose on Amazon and from your local home improvement stores:
Tower Garden Customer Support
Phone: 866-235-0414 (Available M-F 8am-5pm CT)
Orbit Sprinkler System 1/2-Inch x 3/4-Inch x 18-Inch Cobra Flexible Pipe Riser
Thank you for the info!!!