Light cable.

Lights may be incandescent or led. The string may be wire in line (10, 20, 35) or wire in loop (20, 35, 50).

The length of the string:

The string with lights incandescent:
10 lights (wire in line) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 100 cm – it can only be turned on/off by plugging/unplugging it.
20 lights (wire in line) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 220 cm
20 lights (wire in loop) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 110 cm
35 lights (wire in line) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 410 cm
35 lights (wire in loop) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 185 cm
50 lights (wire in loop) - from the mains plug to the first light are 150 cm, the part of the string where the balls are 260 cm

The string with lights led:
10 lights (wire in line) - from the mains plug to the first light are 155 cm, the part of the string where the balls are 130 cm
20 lights (wire in loop) - from the mains plug to the first light are 155 cm, the part of the string where the balls are 130 cm
35 lights (wire in loop) - from the mains plug to the first light are 155 cm, the part of the string where the balls are 235 cm
50 lights (wire in loop) - from the mains plug to the first light are 155 cm, the part of the string where the balls are 340 cm

Distance between balls: 12-14 cm