Supports multiple input voltages.
Provides simultaneous 110VAC and 220VAC.
Cons: No ground without extra part
No UL certification, manual, warranty, or tech support.
I purchased a Seven Star CT2000 2000 Watt step-up, step-down transformer to transform standard US 110VAC to 220VAC to supply a foreign 220VAC only PC. As there are no other reviews for 7 Star transformers, this review is for the product line in general. The unit is made in China.
The CT2000 provides for multiple input voltages (110VAC, 200VAC, 220VAC, and 240VAC) selected via a jumper on the back. The unit has two receptacles on the front, one for 110VAC and one for 220VAC, so it can provide both voltages simultaneously. Other units may have other features.
There is a serious problem with this unit. The power plug is a CEE 7/7 (AKA Type E/F hybrid) compatible with the European Type F or "Schuko". IT DOES NOT FIT STANDARD U.S. SOCKETS !!!
(See en.wikipedia.org/wiki/AC_power_plugs_and_sockets TypeE/F)
Check the product photo and you will see round pins and a small metal receptical where the ground pin should be as well as metal strips down the side. This is a hybrid and compatible with either the European Type E or Type F ("Schuko"). Again it does not fit U.S. sockets. The package usually includes a "universal" adapter to convert the Type E/F hybrid plug to physically fit U.S. Type B sockets, BUT WITHOUT CONNECTING THE GROUNDING PIN !!.
The Seven Star MFV-13 reportedly converts Schuko plugs to U.S. Type B and connects the ground via two metal strips at the top and bottom of the Schuko. The MVF-13 is available from various electrical mail order houses for about $10 + S&H. Typically this is an extra part the user must purchase seperately, and is usually not told about.
Before I found out about the MFV-13, I went ahead and replaced the original power cord with a regular U.S. three wire cord and U.S. Type B plug. The unit seems to work OK and is now properly grounded. Only people knowledgeable about electrical power systems should attempt this otherwise you can miswire it and create new safety problems.
Reviews on other sites have complained about the delivered product having different output sockets than shown in the ad. Be aware that different models have different sockets and the unit pictured in the ad may not be the unit delivered.
The unit has a CE mark, but no UL certification. The installed fuse is rated for 20A at 250V.