ORIGINAL NOVOFLEX 400MM F5.6 WITH PISTOL GRIP. ORIGINAL PISTOL GRIP. I HAVE BEEN TOLD BY MY REPAIR MAN TO GET THE DUST FROM THE REAR. OPTIC IS TO USE A LARGE CLEANING CLOTH FOLD IT UP AND USE A ELASTIC BAND AND ATTACH TO A END OF A PLASTIC RULER AND USE IT TO CLEAN THE OPTIC.