Although an increasing number of ECB brokers do now allow trading in microlot sizes, a few still do not,
so it could be an issue if you prefer to trade in Microlots.
In the above example, on the EURUSD, you buy 1 microlot and sell 1 microlot at the same time, then, if the pair goes down 10 pips,
you place an order to sell 3 Microlots and buy 1 microlot.