An electrically-driven device, the device comprising: a handle; a head, the head comprising: a head base being coupled to the handle and movable in at least two dimensions relative to the handle, and a first head attachment and a second head attachment, wherein: each one of the first and second head attachments is releaseably engageable, one at a time, with the head base, each one of the first and second head attachments includes a skin treatment implement constructed to treat skin or a cutting unit constructed to cut hair, the first head attachment is different from the second head attachment, and each of the first head attachment and the second head attachment comprises any one of a shaver head attachment, a long-hair trimmer head attachment, a body hair trimmer head attachment, a beard trimmer head attachment, a facial hair stubble trimmer head attachment, a skin treatment implement head attachment, or an anti-three-dimensional movement head attachment; at least one driven shaft, the at least one driven shaft extending into the head and coupled to and driving the skin treatment implement or cutting unit; a motor, the motor being contained substantially within the handle; and a transmission, the transmission being constructed to translate rotary motion of the motor to linear, reciprocating motion of the at least one driven shaft. a handle; a head, the head comprising: a head base being coupled to the handle and movable in at least two dimensions relative to the handle, and a first head attachment and a second head attachment, wherein: each one of the first and second head attachments is releaseably engageable, one at a time, with the head base, each one of the first and second head attachments includes a skin treatment implement constructed to treat skin or a cutting unit constructed to cut hair, the first head attachment is different from the second head attachment, and each of the first head attachment and the second head attachment comprises any one of a shaver head attachment, a long-hair trimmer head attachment, a body hair trimmer head attachment, a beard trimmer head attachment, a facial hair stubble trimmer head attachment, a skin treatment implement head attachment, or an anti-three-dimensional movement head attachment; a head base being coupled to the handle and movable in at least two dimensions relative to the handle, and a first head attachment and a second head attachment, wherein: each one of the first and second head attachments is releaseably engageable, one at a time, with the head base, each one of the first and second head attachments includes a skin treatment implement constructed to treat skin or a cutting unit constructed to cut hair, the first head attachment is different from the second head attachment, and each of the first head attachment and the second head attachment comprises any one of a shaver head attachment, a long-hair trimmer head attachment, a body hair trimmer head attachment, a beard trimmer head attachment, a facial hair stubble trimmer head attachment, a skin treatment implement head attachment, or an anti-three-dimensional movement head attachment; each one of the first and second head attachments is releaseably engageable, one at a time, with the head base, each one of the first and second head attachments includes a skin treatment implement constructed to treat skin or a cutting unit constructed to cut hair, the first head attachment is different from the second head attachment, and each of the first head attachment and the second head attachment comprises any one of a shaver head attachment, a long-hair trimmer head attachment, a body hair trimmer head attachment, a beard trimmer head attachment, a facial hair stubble trimmer head attachment, a skin treatment implement head attachment, or an anti-three-dimensional movement head attachment; at least one driven shaft, the at least one driven shaft extending into the head and coupled to and driving the skin treatment implement or cutting unit; a motor, the motor being contained substantially within the handle; and a transmission, the transmission being constructed to translate rotary motion of the motor to linear, reciprocating motion of the at least one driven shaft.