Suppose the cost that the market will pay for umbrellas is X. Presumably the Chinese manufacturers have found X and set their prices accordingly and have profit Y per umbrella. Now the price increases by tariff Z - either fewer umbrellas will be sold or Y will decrease to mitigate price increase, or some combination of both.

Tariffs are a tax on imports and in some sense have to be paid by the customer, but they are also a problem for the supplier.