A restricted class of OTC drugs also exists in the U.S. This restricted class includes drugs such as pseudoephedrine, emergency contraception, and some Schedule V controlled substances. These products, while considered OTC, are kept behind the pharmacy counter and must be dispensed by a pharmacist pursuant to proper identification, age verification, and patient education.
The lux (symbol: lx) is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square metre. In photometry, this is used as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface.
Watts are a measurement of electrical power. The symbol for the watt is W and one watt = one joule per second (joule is the unit of energy). So a 60W light bulb converts 60 joules of electrical energy to heat and light energy every second! Volts are the unit of measurement for voltage.