Altar candlesticks hold the candles used in the Catholic liturgical celebration of Mass.
Altar candlestick Wikipedia
These candlesticks consist of five principal parts: the foot, the stem, the knob, the bowl to catch drippings, and the pricket on which the candle is placed.
Before the 10th century AD, altar candlesticks were not used. They were used occasionally by the thirteenth century, and in the sixteenth, they were in common use.
Altar candlesticks may be made of any material suitable for candlesticks, with the exception that silvered candlesticks may not be used on Good Friday. They may never be used for funeral celebrations. Also, they may not be covered by cloth or lace, and candelabra are prohibited, so each candlestick must be distinct.