... Service: Features:Circular slide rule side with clear durable cursor,For calculation and conversion of temperature,time,distance,volume,altitude,speed ... NM, 1:1000,000 NM, Clear rotating disc for lead pencil plotting, For calculation of heading and groundspeed, wind velocity, head ... T/T, L/C ,Paypal, Western Union or others for negotiation.Samples Offer:Kearing will offer samples at reasonable quantity ...