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