Blades, otherwise known as oars to amateurs or non rowers, are used to propel the boat. They are long (sculling: 250–300 cm; sweep oar: 340–360 cm) poles with one flat end about 50 cm long and 25 cm wide, called the blade. Classic blades were made out of wood, but modern blades are made from more expensive and durable synthetic material, the most common being carbon fiber.
The Water Rower comes partly preassembled in two large boxes. The assembly instructions are reasonably good, and as long as you take your time and follow them carefully (read all the text) it takes about 45 minutes from opening the first box to trying it out. I bought bottles of distilled water to fill it, which made it easy to fill using the included funnel & hose.
The benefit of a water resistance rower is that it most closely simulates a boat moving through water. Rowing resistance comes from the effect of fluid drag acting on the boat; in other words, resistance increases according to stroke rate. The patented WaterFlywheel emulates this naturally self-paced benefit of rowing. This is a workout with immediate benefits, regardless of your level of experience! Please also note that you can adjust the workout intensity by changing the amount of water in the tank. The more water, the higher the effort level required.
Being able to easily store your rower is a huge plus. Make sure you investigate how well the machine stores, if it folds up or comes apart easily to be able to put it in your closet, or in other storage areas. As an example, the Concept2 Model D rowing machine folds up nicely by a simple pull pin located in the middle of the rower. Wheels on the bottom allow for easy moving.

In sweep or sweep-oar rowing, each rower has one oar, held with both hands. This is generally done in pairs, fours, and eights. In some regions of the world, each rower in a sweep boat is referred to either as port or starboard, depending on which side of the boat the rower's oar extends to. In other regions, the port side is referred to as stroke side, and the starboard side as bow side; this applies even if the stroke oarsman is rowing on bow side and/or the bow oarsman on stroke side.