These are gold for reconing. The manual gives the exact (352mm), the screw hole pattern (4 holes at 90°, M6 thread), and the gasket thickness (3mm closed-cell foam).
: For models featuring integrated media playback, the U15a-MP3 Manual provides specific instructions on USB interface operations and MP3 format requirements. Key Performance Characteristics Beta 3 U15a Service Manual
This is a technical guide based on the standard maintenance procedures for Beta 3 series pressure washers. These are gold for reconing
The manual defines the operational limits and internal hardware of the U15a unit: Beta 3 U15a Service Manual