The Grip for Double Joy-Cons is a grip that holds both Joy-Cons in a more comfortable angle than the Joy-Con grip that comes with the Switch. Instead of holding the grips parallel, it angles them so they match the angle of the users arms, keeping the wrists straight.
This device is designed for users who have difficulty with the angle of the Joy-Cons on the double Joy-Con grip that comes with the Nintendo switch. This grip holds two Joy-Cons (- and +) in the dual-controller grip orientation.

Original website: https://github.com/makersmakingchange/grip-joy-con-double/blob/main/README.md

Print Settings:
0.2 mm layer height
20% infill
No Supports

Total print time: 257 minutes
Total number of components: 1
Typical total mass: 27g
The device can be printed in any colour of PLA

Remove supports
Clean support area with hobby knife and sandpaper