The town of Volosovo, near St Petersburg, is booming. Not the economy - it's the loudspeakers. Like many towns in Russia, Volosovo has them installed on tall poles that line the main street. Traditionally they are used for playing patriotic music during national holidays. Now, though, they have a different purpose. "Two volunteer artillery battalions are being formed. We invite men from 18 to 60 years old to join," the speakers blare out. It's a message that's being repeated up and down this vast country. On social media, on TV and on billboards, men are being urged to sign short-term contracts with the military to fight in Ukraine. In the face of significant losses in the conflict, the authorities have launched a recruitment drive for the Russian army.