Are they all stainless steel, and built of fairly heavy material? Are they on the trailer, or just with it?
If already installed, I would remove them anyway to inspect the grease, and repack. Many bearing buddies are installed and not pumped up the first couple of trips (see previous posts) or else were allowed to go "flat" and provided limited protection.
If they are not on the trailer, repack for sure, then buy the real thing!
I bet somebody else makes a good bearing protector, but there sure are some lousy imitations on the market. People happily buy a boat stereo that costs $500 extra but avoid spending $20 on something that avoids huge disasters and repairs??
Sort of like not adding oil (when needed) to your car motor, just to save money!!
Our oldest trailer- launched 4 days a week - has now completed another year, now 25 years with out repacking and the bearings are still very quiet.
We have one small boat and trailer - that we bought used - that had never had bearing buddies on it. We put in new bearings but the hub was also badly rusted, which ruined the seals in a few weeks, we now use the bearing buddies to just "pump through" fresh grease several times each summer.
Bearing Buddy makes a "seal kit" that that includes a new surface for the seal, I am looking forward to trying that out!
Anyone used those??