5mm jack leaving some of the metal exposed. If you want a rail that definitely isnt heavy duty and cant be moved with only a few items on then this is the item for you, otherwise dont bother. The shoe box arrived in a shipping bag and the box was in horrible condition. This does not work with my Macbook Pro 2017. Goes great with sports wear and khakis! It also has bluetooth 5. btw, its waterproof for those of you that feel the need to keep it close to sources of water (for whatever reason) and are about as co-ordinated as a brick through a window. This is actually the second closest Ive ordered this year from this company and both collapsed. One is the fit, but like I have just implied, I think that is an isolated thing with my ears on account that they could be oddly shaped. Restituisce malapena >90 mWatt di potenza, dai su!