For 20 years, Skymark designed a line of self-contained air conditioning units, which have now become obsolete. In addition, Skymark also supplied Johnson Controls with York brand products for many years. Ultimately, Johnson Controls acquired Skymark International in 2007, helping to expand its HVAC product line. Whether you have a new or obsolete unit, Nationwide Coils can create its direct replacement coil. This includes coils for model series D3SK, AC, CN, D4HH and DH. Just contact us with your existing unit or model number.