Specifications:
Connector Type: RJ11 6P4C Male to Dual Female.
External Material: Plastic.
Color: White.
Cable Length: 13cm/5".
Size: 2.8 x 2.7 x 2.1cm/ 1.1 x 1 x 0.83".
Quantity: 2pcs.
Package Weight: 30g.
These splitters works great in this situation because it gets the splitter away from the jack a bit with the flexible cable.
It can be easily installed on the phone and handset without any tools.
Does not affect the sound quality because of the advanced technology and high-quality materials.