Our standard turning inserts are made with a CBN or PCD tip brazed to a carbide blank. The size of the tip is a significant factor in the cost of the insert, and determines the maximum depth of cut the tool can take. The three tip selections available as standard are shown as DT, 5 and 7 in this online catalog.  DT stands for Double Tip. The tool has a small tip on opposing ends, providing two cutting edges on one insert. The tip size is larger than what our competition generally provides us on a "throwaway" or "one use" insert, and this tool may be reground for a second use, if the condition of the used tool allows it.  The leg length varies with radius, and approximate leg length available for standard radii are shown below. The 5mm tip (this denotes the size of the triangle used for grinding) has been the general standard for the industry for many years. The 7mm tip is used in applications where heavy depths of cut or chip flow dictate the extra leg length.  On inserts smaller than .375" (9.53mm) I.C., leg lengths may be less than shown due to size limitations of the insert. 

Example of Approximate Leg Lengths for an 80 degree Diamond, 1/2" I.C. (CNMA43X) Insert
Approximate Leg Length by Type and Radius
.015" (.38mm) Radius
.031" (.79mm) Radius
.047" (1.19mm) Radius