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