Emergency hammer v2

This is a new version of http://www.thingiverse.com/thing:1213489
With the same concept, there's a new design that should keep all functionalities and also solve some problems exposed by other users.

Actually there's more mass, a little bit more of 600 gr. The punch is a ceramic drill bit. Now all the mass is in a little area and made with a material stronger that glass.

One of the problems is use the hammer underwater. The v2 shape is designed to be used with 2 hands to apply more power. You can use like a standard hammer using your arm as handle.

The mass can move free inside the hammer to reduce the rebound effect. The holes for mass can be filled with standard metric thread or better with steel bar. Each hole has aerator to make the movement easy.

The seatbelt cutter function and the whistle can not be placed in the hammer, so there's a second part to acomplish this function.

Both elements are subjected with a simple support. This support can be attached with a dou