1870-1876 - Early bustle.
This version is a full flounced petticoat with extra length in the back to fit over a bustle.
1877-1882 - Natural Form.
This version has a slim front and does not fit over a bustle. Suitable for under Tie-Back style skirts. Also works well for 1890-1891 slim skirts.
1883-1889 - Late Bustle.
This petticoat has the slim front needed for this era, plus has a full back with extra length to fit over a bustle.
1890-1897 - Bell Epoch.
This skirt has the full front needed to hold the wide skirts fashionable during this period. Does not fit over a bustle.