they-re slightly different, i don"t know which one to choose
here are the links:
http://www.alza.cz/EN/noctua-nf-p12-pwm-d289676.htm
http://www.alza.cz/EN/ventilator-noctua-nf-p12-d84100.htm
here are the links:
http://www.alza.cz/EN/noctua-nf-p12-pwm-d289676.htm
http://www.alza.cz/EN/ventilator-noctua-nf-p12-d84100.htm