battery tray, new modification I made this modification because someone offered good $$ for the yellow tray and I could not resist the $$$
The second photo showed cut short 3mm screw. The battery tray is mounted on 5mm thick M3 nuts, so I cut 8 pieces of 3mm screws down to 2.5mm thread height, then screws 'bite' into the 5mm think M3 nut from top and bottom engages 2.5mm each. Rock solid!