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