Here is a set of two 1607-RS sealed mobility scooter & power chair wheel bearings.
These 7/16" caster bearings (1607-RS) are an odd size for mobility bearings, and can sometimes be difficult to find. Most often they are found on Invacare power chair caster wheel assemblies.
Check your existing bearings for the series number, which is usually etched into the side of the bearings.