Kramer-Nevins Sinus Lift Instrument (IMP6577SC-5) for acute angles with SMALLER Spoon blades width on one side compared to IMP6577SC . Spoon Blades width (4 mm/5 mm). The acute design will facilitate access to the mesial, distal, superior or inferior aspect. Designed to further separate the sinus lining from the bone, without fraying or tearing. IMP6577SC-5