Steel pipes for thermal equipment, petrochemical industry, machinery manufacturing, geological drilling, high-pressure equipment, etc.; according to the production process, they are divided into seamless steel pipes and welded steel pipes, of which seamless steel pipes are further divided into hot-rolled and cold-rolled (drawn) Two types, welded steel pipes are divided into straight seam welded steel pipes and spiral seam welded steel pipes.
http://www.tszxsteel.com/steel....-pipe/carbon-steel-p

Fixed tine rake. The fixed nail-tooth harrow is composed of nail teeth, rake frame, traction mechanism (or suspension mechanism), etc. The nail teeth are fixed on the tooth bar of the rake frame, and their relative position remains unchanged, and the depth of the rake into the soil depends on the quality of the rake. According to the nature of the nail teeth to adapt to the soil and the size of the rake depth, it is divided into three types: light, medium and heavy.
http://www.sungardentools.com/rakes/leaf-rakes/

Air coolers have some significant advantages over fans.
(1) The installation site of the air cooler is not limited by the water source, water quality, water intake and other conditions.
(2) The installation and arrangement of the air cooler is not limited by the specific requirements of the water supply and drainage facilities.
http://www.rtfansgroup.com/air-coolers/

Besides, there is another equipment using hihg voltage. The high voltage divider is a special instrument for on-site measurement, which can measure both DC high voltage and AC high voltage. The whole equipment consists of a voltage divider and a measuring instrument. The voltage divider adopts a balanced equipotential shielding structure, and high-quality electronic components are used inside the completely sealed insulating cylinder, so that the entire device has accurate testing, good linearity and stable performance.
http://www.mktester.com/high-v....oltage-tester/high-v

In addition to dumbbells, barbells are also the most used equipment in fitness. I believe everyone is familiar with the movement of barbell bending over rowing, because this movement is the movement we use the most when exercising the back muscles. The advantage of the barbell movement is that it can combine the muscles on our body to exercise, just For example, the barbell bent over rowing action, when we do this action, not only the latissimus dorsi, but the entire back muscle will exert force.
http://www.luchfitness.com/free-weight/barbell/