PowerBlock "The Block" adjustable dumbbell set, $10.

The ingenious PowerBlock ‘The Block’ takes what would be an entire set of 18 weight lifting dumbbells, weighing from 5 to 45 pounds, and packs them into the space of two dumbbells.

The PowerBlock dumbbell is relatively simple in principle. Each unit is composed of a central five-pound dumbbell that is nested inside eight progressively longer sections, each of which weighs five pounds. By adjusting the pin on the side of the Block, you regulate how many of these sections are picked up by the center piece when it is lifted up.

The colored sleeves seen on the side of the Powerblocks in the photos below used to correspond with a color coded sticker mounted on the top of the Blocks, which told you where to stick the pin to get the weight you’re after. However, somewhere along the line this set lost that sticker.   

Something to note here is that this particular set of Blocks is a rather early example, and the company has since branched out into different - and different looking - products. This means that you owe it to yourself to check out the company’s more recent offerings so that you’ll be familiar with them when you see them. Power Block stuff is expensive!

Now, what about shipping these monsters? Glad you asked! It just so happens that each one of these units fits right into a USPS large flat rate box, which (currently, anyway) costs around $15 to ship anywhere in the U.S. So, for a mere $30, you can get both of these Powerblocks to anywhere the USPS will ship their flat rate boxes - including Alaska and Hawaii!

This pair of Powerblock ‘The Block’ personal dumbbells sold on eBay for $228.