Coaster - Slate Mum Fuel Mum Fuel Slate Coaster £2.99 Personalisation:: Personalisation required 0 characters left. £2.99 Add To Basket Mum Fuel - what every mum runs on. This square slate laser engraved coaster will look great in your home! It would also make a stylish and elegant gift idea for mum. Please note that these are a natural slate product and as such each will have its own unique character. Rough edges will be different on each coaster.