The retractable tube is stored inside the body of the pump when not in use, and it can attach to either a Schrader or a Presta valve, the two types of valves you’ll see. Some pumps can accommodate only one type, making them less universal. Toggling between the two is simple, which can’t be said of other models with itty parts that require nerves of steel to handle on a good day, let alone while wearing gloves, crouching in the wind, oblivious to the sewer grate a few feet away.
Mini Pump:   This actually goes on the frame of your bike, as it’s a bit too big for most under-seat bags.   Coming soon, we’ll have a review from Bill of his very favorite one, but a good pump is a lifesaver.    Some people instead carry a CO2 inflator, which is faster and easier to use but does require disposable cartridges, and each time you have a flat, you’ll need at least 2 of those cartridges.  There are combined pump/inflator tools that we’ll also talk about soon.
It is a good solid stand made mostly from heavy metal, but it does have a couple of problems. (I will use part names from the instructions to explain.) First, the clamp between the "telescopic bar" and the "upright" is plastic. It arrived broken in the box. Whoever boxed it should understand that if you put it in the box broken, the customer will remove it from the box broken. I did not return it as broken because I was able to Gorilla Glue it back together and it works fine; it clamps tight enough to hold the telescopic bar in place. Second, the "bike support stand" (the horizontal bar at the top that holds the bike), when attached to the seat support does not grip tight enough to hold the bike in the position I set because there is too much weight from the front of the bike. The torque causes the bike to rotate until the front wheel is on the ground. That is not enough for me to return the stand because I seldom work on the front wheel and if I do I can attach the stand to the top horizontal of the bike frame. I think they could fix the problem by not making the "bike support stand" so smooth, give that part a sandpaper like finish or put rubber fingers inside the clamp so the part does not slip under the torque from the weight of the front of the bike. I might rough up the stand part with sandpaper, or put small grooves in it to give the clamp something to grip on to see if that solves the problem. Third, the clamp holding the bike frame even at full tight will not keep the bike from rotating around the frame. It is not enough for me to send the stand back, just a minor annoyance. The problem is there is smooth plastic trying to clamp a smooth metal frame. I think they could fix this by putting thin rubber pads in the clamp. I will probably run out and get some pads to try that out. I think it is a good stand for the price. The stand itself is made from much heavier metal than I expected. It is very stable with the four legs. I easily overcame all the issues so I kept it.
Otherwise, this tool should serve the average commuter well. Specifically, we think you’ll find the size 4, 5, and 6 hex keys, extremely common sizes in bicycles, very helpful. They’ll adjust seat-post heights or let you remove the saddle entirely, or tighten a loose stem that’s always rattling apart. The Phillips head will tighten loose bolts on shoe cleats or the rear derailleur. The most common use for the torx would be adjusting disc brakes if you have ’em.

Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.