"I'm using these as grab handles when entering / exiting my garage loft and stepping off / onto a ladder - otherwise an awkward exercise if carrying something heavy. They are the ideal size for this purpose. Four smallish screws locate each end plate adequately, though the plastic mounting 'gives' a little under strain. I doubt you'd pull them out though! There's a concealed extra fixing bolt at each end that looks like 8mm thread. Too short to fix through 75mm joist though. I tried a longer 8mm bolt but discovered that the thread is not 8mm - I didn't know manufacturers used non-metric anymore."
"Heavy duty and more versatile than expected as they came with long machine screws so that they can be fastened through e.g. a door, and you do not have to rely on just the 4 smallish screws in each base-plate."