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