SL Series. SLF Center Stroke Mallet that offers heel, toe and sole weighting with grams of tungsten blend. The SL Series uses the original Slotline Inertial Putter design with updated materials and technology. Slotline SL Series Putters. REVIEWS; DESCRIPTION. . There are four putters in this series. The Slotline SL The SL Series includes: SLF Hi-Moment Offset, SLF Hi-Moment Non-Offset, SLF New Moment, and the SLF Center Stroke Mallet. SL CNC Aluminum “CNC milling and Tungsten weights keep the ball on. Email to a Friend · Share Facebook · Share on Twitter. The SLF is available from TGW for $ The SL Series. All Slotline Putter Kits come with a head, shaft, choice of grip and head-cover. Price: $; Product Code: slf; Manufacturer: Slotline; Availability: Discontinued; Model: Hi-Moment Offset, Hi-Moment.