Pretty sure 1 they are standard, measure ID of the spring I, and OD of the shackle or bolts, no picture of the leaf .
Make sense, northern tool carries a lot of trailer parts, tractor supply also. Stay away from boat stores, automatic 60% price hike. Cause the tailer starts with the word boat .
If that fails just search the ID and OD measurements and add the word bushing some thing will pop up.