Backup wrench for power tong

The backup wrench assembly of claim 23, wherein:

• the wrench head defines a rotation axis position;
• the first insert is dimensioned to receive the first sucker rod such that a first rotation axis of the first sucker rod is at the rotation axis position;
• and
• the second insert is dimensioned to receive the second sucker rod such that a second rotation axis of the second sucker rod is at the rotation axis position.

The backup wrench assembly of claim 23, wherein each of the first and second inserts comprises:

• an insert opening having an insert opening size for receiving a corresponding one of the first and second sucker rods, and
• a positioning part for positioning the corresponding one of the first and second sucker rods received in the insert opening, wherein each insert complies with:
• A
• =
• T
• -
• 1
• 2
• ⁢
• B
• ,
• wherein A is a longitudinal extent of the positioning part, B is an insert opening size, and T is a longitudinal distance from and including the positioning part up to a rotation axis position of the wrench head.