Muffler (silver) and exhaust pipe on a Ducati 695 motorcycle. A muffler (silencer in English) is a device for reducing the amount of noise emitted by the exhaust of an internal combustion engine.
Quick Answer. Normal blood sugar levels should be  less than 100 mg/dL when fasting and less than 140 mg/dL two hours after eating, according to WebMD. People without diabetes tend to have blood sugar levels of around 60 to 90 mg/dL before eating.
In most humans this varies from about 82 mg/dl to 110 mg/dl (4.4 to 6.1 mmol/l). The blood sugar levels rises to nearly 140 mg/dl (7.8 mmol/l) or a bit more in normal humans after a full meal. In humans normal blood glucose levels are around 90 mg/dl, equivalent to 5mM (mmol/l).