Glanville and Mary Turner, who also served as the lead puppeteers. Glanville and Turner's team built the 13 members of the main cast in six months at a cost of between £250 and £300 per puppet (about £ and £ in ). Since pairs of episodes were being filmed simultaneously on separate stages, the characters needed to be sculpted in duplicate. Facial expressions were diversified by means of replaceable heads: as well as a head with a neutral expression, each main character was given a "smiler", a "frowner" and a "blinker". The finished puppets were about tall, or adult human height. The puppets were made up of more than 30 individual components, the most important of which was the solenoid that synchronised lip movements with the characters' pre-recorded dialogue. This device was positioned inside the head unit; consequently, torsos and limbs appeared relatively small. The puppets' likenesses and mechanics are remembered favourably by puppeteer Wanda Brown, who preferred the Thunderbirds marionettes over the accurately-proportioned ones that first appeared in Captain Scarlet: "The puppets were easier to operate and more enjoyable because they had more character to them ... Even some of the more normal-looking faces, such as Scott and Jeff, for me had more character than the puppets in the series that came afterwards." Rimmer speaks positively of the puppets' still being "very much caricatures", since it made them "more lovable and appealing ... There was a naive quality about them and nothing too complex." The appearances of the main characters were inspired by those of actors and other entertainers, who were typically selected from the show business directory Spotlight. According to Glanville, as part of a trend away from the strong caricature of previous series, APF was seeking "more natural faces" for the puppets. The face of Jeff Tracy was based on that of Lorne Greene, Scott on Sean Connery, Alan on Robert Reed, John on Adam Faith and Charlton Heston, Brains on Anthony Perkins and Parker on Ben Warriss. Sylvia Anderson brought the character of Penelope to life in likeness as well as voice: after her test moulds were rejected, sculptor Mary Turner decided to use Anderson herself as a template. Main character heads were initially sculpted in either Plasticine or clay. Once the general aspect had been finalised, this served as the template for a silicone rubber mould. This was coated with Bondaglass (fibreglass mixed with resin)