The Alpen F4 Forte SDS+ hammer drill bit range has a patented 4X stepped profile and patented tip.
Low wear, very long service life.
A high efficiency drill bit for heavy-duty drilling in concrete, natural stone and brickwork.

Overall length 310mm with a drilling depth of 260mm. 

We do recommend that an SDS+ hammer bit of 310mm overall length should be the longest length used without pre-drilling a pilot hole.

As a drill bit gets longer in length, potentially the force behind an SDS+ drilling machines hammering action could gradually dissipate through the length but a long drill bit could also whip, easily bend under drilling pressure and go out of shape.