Answer:
agency shop agreements.
Step-by-step explanation:
The agency shop agreements are agreements under agency shop unions which does not require workers to join the union but workers need to pay service fees to the union to meet the expenditure of collective bargaining.
The agency shops also allows employers to recruit both union or non-union workers and the recruited workers does not necessarily need to join the union to remain as an employed individual.
Therefore, under agency shop agreements, workers are not required to join the union, but those who do not join are still required to pay a union fee or regular dues to the union.