An electrically erasable programmable read-only memory EEPROM uses voltage to erase memory. Ballpoint pens with erasable ink were pioneered by the Paper Mate pen company. EPROMs (Erasable Programmable Read-Only Memory) are erased by exposure to UV radiation. Butanone is also used in dry erase markers as the solvent of the erasable dye. Early microcontrollers relied on erasable programmable read-only memory (EPROM) devices to hold the application program. Unlike standard highlighters, they are easily erasable. Variants starting with 87 have a user programmable EPROM, sometimes UV erasable. As of 2005, most CPLDs are electrically programmable and erasable, and non-volatile. The Microchip website lists PICs that are not electrically erasable as OTP. An EPROM is an erasable ROM that can be changed more than once. For example, rubber cement is used as the marking fluid in erasable pens. Some companies offer erasable colored pencils for beginning artists to experiment with. Block II had 36 kilowords of fixed memory and 2 kilowords of erasable memory. UV erasable windowed versions of these chips can be ordered. The lowest bank (bank 0) was erasable memory (RAM).