Shelley was a key member of a close circle of visionary poets and writers that included Lord Byron; Leigh Hunt; Thomas Love Peacock; and his own second wife, Mary Shelley, the author of Frankenstein.
If the 900 watts means the input power, then 1000 w inverter would be ok. If the microwave produces 900 w of cooking power, you will need a bit more, maybe 1200-1400 w if you don't know what the input power rating of the microwave is.
MICROWAVE HOOD COMBINATION SAFETY. This product is suitable for use above electric or gas cooking products up to 36 (91.4 cm) wide. These installation inst ructions cover different models. The appearance of your particular model may differ slightly from the. illustration in these installation instructions.