The DIM divisor is used to calculate the dimensional weight of the package. Dimensional weight is calculated by Length times width times height then divide them by the dimensional divisor - Also called DIM divisor.
Example:
A package that has dimensions of 10 x 20 x 30. So that's 6000. Then let's say the shipper has a DIM divisor of 166. Then We divide 6000 by 166 and we get 36.14 as their Dimensional weight.
The higher the DIM divisor is, the better it will be for the shippers, since they will have a lower Dimensional weight that will impact a lower cost for the shipment. That is why this is something that the shippers also negotiate with the carriers during the negotiation stage.
So from our dimension example scenario earlier, if the shipper has 200 DIM divisors, then we divide 6000 by 200, then we get a dimensional weight of 30 instead, which should be a lower cost than 36.14.