Berg is designed for distinct shots, where you don’t need to worry about the disc hoovering far passed the basket. It's a slightly overstable putter with low glide and has a very predictable flight patch. The disc features an ergonomic thumb track which is prominent on the top side while not being noticeable at the bottom.
Kastaplat's K3 material is a soft, supple blend that has a tacky, grippy feel. Compared to other base plastics, K3 is best described as medium soft.