This part is a kind of semiconductor called ANR-05K680.
Function of this product has ZINC OXIDE VARISTOR.
Manufacturers : Ancol
Image and pinout :
Some of the text within the PDF file :
ZINC OXIDE VARISTOR Ancol FEATURES: l Widely voltage range 1 8v-1 .8kv l Fast response to the rapidly increase Voltage (Mu sec.) l Excellent non-linearity voltage l Symmetric V-I characteristics l Great withstanding surge current (200 0A/c m2) l No follow-on current l Long life HOW TO ORDER A NR 05 K ① ② ③④ 180 T ⑤⑥ ①②③ Ancol Electronics Co.,Ltd Non-Linear Resistor (mm) Element Diameter 05 5 40 40 ④⑤⑥ Tolerance K ±10% M ±20% (V) Varistor Voltage 180=18*100 181=18*101 Packaging B Bulk T Tape & Reel 182=18*102 Characteristics pre breakdown nomal operating upturn Region region region Current(A) Fig1 Voltage Current Characteristic TEST CONDITIONS Item Operating Temperature Range Storage Temperature Range Varistor Voltage Max Clamping Voltage . [ ... ]