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