Abstract: A wearable device includes a host, a first belt, a second belt, a circuit board, a cable, and an adjustment mechanism. The first belt, one end of which is connected to a first side of the host, has a cable holding part. One end of the second belt is connected to a second side of the host. The circuit board is disposed at an overlap of the first belt and the second belt. A first end and a second end opposite to each other of the cable are connected to the circuit board and the first side respectively, and a holding section of the cable is fixed to the cable holding part. The adjusting mechanism is disposed at an overlap of the first belt and the second belt to adjust an overlapping length of the first belt and the second belt.

Abstract: A hydrometer comprises a transparent container including a top opening, two arcuate dividers extended from both sides of top opening for dividing the interior of container into a measuring chamber and two opposite side channels each having a bottom open end in communication with measuring chamber and a top inlet open to outside, and a pointer pivotably mounted inside measuring chamber and adapted for indicating a specific gravity of liquid (e.g., sea water) contained in measuring chamber A fluid path is formed from top inlet through channel and bottom open end into measuring chamber as container immersed in the liquid to be measured. This can avoid the generation of bubbles. Further, the time(s) of adjustment of the specific gravity of liquid can be precisely determined.

Abstract: A hydrometer comprises a transparent container including a top opening, two arcuate dividers extended from both sides of top opening for dividing the interior of container into a measuring chamber and two opposite side channels each having a bottom open end in communication with measuring chamber and a top inlet open to outside, and a pointer pivotably mounted inside measuring chamber and adapted for indicating a specific gravity of liquid (e.g., sea water) contained in measuring chamber A fluid path is formed from top inlet through channel and bottom open end into measuring chamber as container immersed in the liquid to be measured. This can avoid the generation of bubbles. Further, the time(s) of adjustment of the specific gravity of liquid can be precisely determined.

Abstract: A water filtration and aeration system fastened to an aquarium to let gas (CO2, O.sub.2) be admitted in minute bubbles into water and then to let treated water be guided back to the aquarium. The system includes a gas diffusing unit, a flow guide assembly connected to the gas diffusing unit by a coupler, and an extension cylinder coupled to the flow guide assembly at the bottom. Gas and aquarium water are guided downwards to a mixing chamber in the coupler where they are mixed by a motor-driven vane, then treated water is guided by the flow guide assembly to flow out of the extension cylinder to the aquarium again.