The ornamental design for a contactunit for an animal training system, as shown and described.
FIG. 1 is a top perspective view of a contact unit for an animal training system showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a left side elevational view thereof; and,
FIG. 7 is a right side elevational view thereof.
The broken line showing of structural features and indicia is included for the purpose of illustrating portions of the contact unit for an animal training system that form no part of the claimed design.