Sinus Lift Obtuse Angles, IMP6578 Description: Kramer-Nevins Sinus Lift Instrument for Obtuse Angles. Spoon blades width (4mm/7.4mm). The acute design will facilitat access to the mesial, distal, superior or inferior aspect. Designed to further separate the sinus lining from the bone, without fraying or tearing. IMP6578 or 6578