Type I Borosilicate Glass is higher quality and more resistant to thermal shock than common Type III soda lime glass. Type I borosilicate glass is less subject to thermal stress and is commonly used for the construction of reagent bottles and labware. Well known makers of Type I glass include Pyrex® and Duran®, among others. The common type of borosilicate glass used for laboratory glassware has a very low thermal expansion coefficient (3.3 x 10−6/K), about one-third that of ordinary soda-lime glass. This reduces material stresses caused by temperature gradients which makes borosilicate a more suitable type of glass for certain applications. Type I borosilicate glass is more expensive than soda lime glass due to its superior construction, but less expensive than Quartz glass, which is best available and generally not used in labware.