2 each 3" long, 1 1/4" high, .350" thick Joiner channels. 2 each 9" long x .860" high x .138" thick Joiner Spars.
I am unclear why there are two sockets and two spars in this kit. Seems like you'd only need one spar. None the less, this is the same kit used in the SIG 1/3 scale Spacewalker.
A wing joiner ties the separate panels of a built-up wing together, transferring load across the center of the airframe so the halves act as one structure. On models with a two-piece or multi-panel wing, the joiner is a key part of a sound assembly.
This category features the Sig Wing Joiner kit, which supplies the joiner components used to align and connect wing panels during construction. Parts like these are commonly installed as the wing is built up and the panels are brought together at the correct dihedral angle.
Where a Joiner Is Used
Wing joiners are typical on trainers, sport models, and gliders built with removable or sectioned wings, where a strong but serviceable connection is needed. A properly fitted joiner helps the wing carry flight loads without flexing at the joint.
Take a look at the listing below to see the wing joiner kit offered here.
 "Sig Wing Joiner kit")
