Our shower head and handheld unit 1000 055 745 has a failed seal. We have owned it 15 months. It has a lifetime warranty. How do we get parts and the triangle shaped tool to repair it or replace it?

Glacier Bay is a Home Depot private brand.

The Model number is
Model # 8474100GB


The number you provided is the SKU number.

Go to Home Depot, find same product (and hope fully the same SKU number).
On the package you should find a phone number to contact about warranty. You will probably be told to return the defective unit for credit.