binance.websockets.trades()

[Raspberry42]

Hello, How many elements can I put in this array?
Thank you in advance.

let array = ['BNBBTC', 'ETHBTC']

binance.websockets.trades(array, (trades) => {
  let {e:eventType, E:eventTime, s:symbol, p:price, q:quantity, m:maker, a:tradeId} = trades;
  console.info(symbol+" trade update. price: "+price+", quantity: "+quantity+", maker: "+maker);
});