It's a plastic box that slides in under the seat, similar to this one

I do have the passenger door still attached (of course), but I've got the side pockets filled with various loose items. Probably need to move them to a better spot, in the trunk. Never had the BMW first aid kit, though.

The mesh pocket will just keep items under the seats (both seats are already set to our favorite positions, so they're never moved) from sliding forward, but maybe should just use the glove compartment, instead, on the passenger side.

But, on the driver's side, I'm absolutely needing this...the lockbox weighs about six lbs, and might slide under the brake pedal, so I'm going to use a mesh pocket there, to eliminate the problem. I'm planning to use some 3/4" or 1" self-drilling screws to mount the bottom of the pocket's frame to the raised metal under the seat, and secure the upper corners to the seat itself, using zip ties. The elastic nature of the pocket will allow insertion and removal of the two boxes, but hold them in place until needed. Out-of-sight, but handy. I'll get the pockets sometime today....

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01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide