Generally speaking ,for cooling 100W Coherent or Synrad metal RF laser marking machine, we recommend S&A chiller model CW-6000 with 3KW cooling capacity; CW-6000 technical parameter: http://www.teyuchiller.com/Products/ChillerCW60003000Wco.html For cooling 150W Coherent or Synrad metal RF laser, S&A chiller model CW-6100 with 4.2KW cooling capacity is suitable for it; CW-6100 technical parameter: http://www.teyuchiller.com/Products/ChillerCW61004200Wco.html For cooling 200W Coherent or Synrad metal RF laser,S&A chiller model CW-6200 with 5.1KW cooling capacity is better. CW-6200 technical parameter: http://www.teyuchiller.com/Products/ChillerCW62005100Wco.html CONTACT S&A TE:+86-20-89301885 FAX:+86-20-84309967 SKYPE: teyuchiller Email:marketing@teyu.com.cn Website: http://www.teyuchiller.com