This type of sockets with 0.78 mm diameter hole, it suits for those cables which are made by 0.78 mm pin connectors
DIY IEM Female Socket Jack for Custom In-ear Monitor Inears Earphone Pin Plugs 0.78 mm
DIY pin plugs for custom IEM projects. Contacts and solder tails are Gold plated Beryllium Copper. The mold is made of clear polypropylene. Dimensions are roughly 3/16″ (5mm) x 3/16″ (5mm) x 1/8″ (3.5mm) with 1/4″ (7mm) solder tails. Modify your IEMs and give them removable cables, or use these to hold the pins when making your own custom cables. Price is for a pair as shown in pictures below High quality, same model as used in high end custom IEMs from JH Audio and others.