Rigid Spacers for Jumpers

Выражение встречается в следующем контексте:

Rigid Spacers for Jumpers
Jumpers at tension points shall also be fitted with spacers so as to limit the length of free conductor to 3.65 m and to maintain the sub conductor spacing of 450/457 mm for quad ACSR ‘Phesant’. Bidder shall quote for rigid spacer for jumper. It shall meet all the requirements of spacer used in line except for its vibration performance. Spacers requiring retaining rods shall not be quoted for jumpers.

Заранее спасибо