（1）   W — bandwidth;

(2) A0 — represents the length of the bottom of the slot;

(3) B0 — indicates the bottom width of the slot;

(4) D — diameter of positive circular side hole;

(5) D1 — diameter of middle hole;

(6) D2 — diameter of elliptical side hole;

(7) E — the distance (width) from the horizontal bisector of the round side hole to the upper boundary of the round side hole;

(8) F — distance from half of the whole slot to the horizontal line of the positive circular side hole;

(9) K0 — depth of slot (second level depth);

（10）               K1 — the first level depth of the slot;

（11）               P0 — distance between vertical bisectors of two adjacent side holes;

（12）               P — distance between two phases of the slot and the bisector of the whole slot;

（13）               P2 — refers to the distance between the entire slot bisector of any slot and the vertical bisector of adjacent side holes on both sides;

（14）               T — thickness of material strip;

T2 — represents the bottom thickness of the strip after forming.