Azer Scientific Control SLIDE Iron. The color change is attributed to the strong magnetic force between the two glass slides. Therefore slides containing iron must be "chromochromic.". Once exposed to air for an extended period of time an undesirable color change is noticed. The color change is attributed to the coating being applied. The coating on the control slide therefore causes the color change. All slides with iron control areas are to be metallized (reduce the amount of iron exposed to the air). The control slide then functions as a control slide. The area to be analyzed is typically the color change that is produced when a control slide is metallized. The color of the control slide is determined by the color change indicator in the color change indicator window. Specifications for Azer Scientific Control SLIDE Iron ESCS-118: Manufacturer: Azer Scientific Quantity: 10 Package Contents: Azer Scientific Control SLIDE Iron ESCS-118 (Please note that the description and stock photo may not correspond to the specific model listed above) For a complete list of products offered by Azer Scientific please visit our Azer Scientific page. Don't forget to check out the extensive collection of Azer Scientific Laboratory lids or covers or coverslips and a wide array of Laboratory lids or covers or coverslips from other quality brands. We offer FREE SHIPPING on most products over the value of 49.95. You may reach us by phone email or live chat We have a 100percent Satisfaction Guarantee to ensure that every laboratory product you receive is exactly what you are looking for Contact us TODAY Filling out our RFQ is very simple and we are more than happy to have the opportunity to work with your procurement department to get the best quote for any particular product you have in mind. Azer Scientific Control SLIDE Iron ESCS-118