A bedslide has a minimum of 4-1/2" height with another 1/2" of height available at the handle end to clear some tailgates. Tundras have a bit more available depth to their beds than GM. Many standard poly gas cans of the 6.5 gallon variety will fit under the cover, particularly if the pour spout is correctly stored inside the can for transportation. Metal DOT approved safety gas cans of the same size will not. My 2k Yamaha inverter generator would not fit in most trucks with this setup. To my knowledge, Bedslide brand is the shallowest depth available. IMHO - good idea in concept, but sacrifices too much space for limited use.
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the courage to offer valid input to those who are open to another way of thinking,
and the wisdom to shut myself down whenever I get too in love with my own misconceived brilliance.