Abstract: The unit comprises a tubular filler, provided with an internal thread) suitable for coupling with a corresponding external thread of the mouthpiece of the tank, and with, internally, a plurality of essentially coplanar anchoring prominences which, in the fitted condition, rest on part of the top edge of the mouthpiece of the tank to which they are constrained by fixing elements in such a way as to prevent the unscrewing of the filler. The anchoring prominences have respective retention elements protruding radially towards the centerline of the filler and capable of being opened out elastically towards the outside. The unit also comprises a filter with, at the top, an annular flange protruding radially towards the outside.

Abstract: The unit comprises a tubular filler, provided with an internal thread) suitable for coupling with a corresponding external thread of the mouthpiece of the tank, and with, internally, a plurality of essentially coplanar anchoring prominences which, in the fitted condition, rest on part of the top edge of the mouthpiece of the tank to which they are constrained by fixing elements in such a way as to prevent the unscrewing of the filler. The anchoring prominences have respective retention elements protruding radially towards the centreline of the filler and capable of being opened out elastically towards the outside. The unit also comprises a filter with, at the top, an annular flange protruding radially towards the outside.