Calendar Manja. Block calendar Manja. 12 months. For every calendar year. Material: MDF. The family-owned company Boltze has been creating stylish accessories for your home for 60 years with over 300 employees. Boltze products are of the highest quality and catch the eye of every observer. With over 11,000 products, the company offers a wide range of items. However, these products are anything but mass-produced, as their naturally chosen materials result in unique pieces that stand out due to remarkable features, such as extremely sustainable manufacturing.