That being said these are great pieces of equipment. The bags are sturdy and well made, and with care will last for as long as I do. I used them for six days while on a beach vacation. I purchased only the 30 pound bag.
1) roll down easily and fit in a corner of your suitcase adding very little weight.
2) Fill easily on arrival through a nice wide neck. I would scavenge up an old tin can or cup to use as a scoop, rather than your hand as I did.
1) A little larger and bulkier than a 30# kettlebell.
2) Nylon straps, being flexible, take a little getting used to if you are used to using traditional metal kettlebells.
For me, the pro's out weigh the cons and these allowed me to "keep the faith" while on holiday.
The PKS is soft and flexible. This is great for travel. This is also great for reducing impact to your arms when you are learning and developing good technique (essential if you want to work with kettlebells - it should not hurt to train with kettlebells. If you are bruising your arms or overly straining your body, you need to learn better form. I recommend youtube searches for videos by StrengthFirst or Steve Cotter. I have no personal or financial connection to either. They are just great videos and their form is excellent). There are several adjustable kettlebells on the market that have hard metal corners that get in the way of anything you want to do with the bell beyond swinging it. This is one area in which the PKS is truly superior over other adjustable systems.
The PKS comes empty, so you have to fill it yourself. Not a big deal, but it requires a little more time to get the weights correct (see below). The handle itself is quite comfortable to use. It is attached to the body of the PKS by strong nylon, so there is no solid link to connect the handle to the body and stop momentum. Again, not a big deal. It takes a bit of getting used to and does not feel as nice as the solidity of an all-iron or all-steel bell. For the price-point, the pros far outweigh the cons, and the PKS is the best choice if you need to adjust weight, save on space, are on a budget, or are new to kettlebell training and figuring out what weight is best for you.
Building the adjustable kettlebell: After my PKS arrived, I went to the hardware store and bought a 50 lbs bag of gravel, a box of contractor bags, and a roll of duct tape (get the real stuff, not the duck brand). I trimmed the contractor bags to about 1/3 of their length (the bottom 1/3). Using a scale, I weighed out 2kg (4.4lbs) amounts or gravel. The gravel went into the trimmed contractor bags, and I rolled them up and sealed them with duct tape. The finished weights are rectangular in shape, so they can fit into the opening of the PKS. At the end of the process, I had 6 small bags which allowed me to make a kettlebell up to 12kg (~26lbs). I am unable to fit more than 6 bags of gravel into the PKS. Perhaps it would be possible with different shapes or smaller bags of gravel. I decided this was fine for me. I figured I would try it for a while and then switch to bags filled with metal shot, if needed.
I love my PKS. My family members use it often, and I take it with me when I travel. I train daily with kettlebells now, and have gone on to purchase steel competition bells. I prefer the solid steel units for a lot of movements, and although I do not compete I really like the standard size of competition bells over the varied sizes of the cast iron ones. I am glad that I started with the PKS. It allowed me to affordably and easily discover which weights were best for me for different movements. I highly recommend this product to anyone starting out with kettlebell training at home.
It doesn't, It leaks.
Any how; I will go with sand; hope it will not leak.